Turbidity associated with river plumes is known to affect the search ability of visual predators and thus can drive “top-down” impacts on prey populations in complex ecosystems; however, traditional quantification of predator-prey relationships (i.e., stomach content analysis) often fail with larval fish due to rapid digestion rates. Herein, we use novel molecular genetic methods to quantify larval Yellow Perch (YP) in predator stomachs in western Lake Erie to test the hypothesis that turbidity drives variation in larval predation. We characterize predator stomach content DNA to first identify YP DNA (single nucleotide polymorphism) then quantify larval YP predation (microsatellite allele counting) in two river plumes differing in turbidity. Our results showed elevated larval YP predation in the less turbid river plume, consistent with a top-down impact of turbidity on larval survival. Our analyses highlight novel ecological hypothesis testing using the power of innovative molecular genetic approaches.
Yellow Perch predation data
Presence/absence and number of Yellow Perch (YP) detected in predator fish stomachs from the western basin of Lake Erie. Data generated using SNP and microsatellite analyses respectively. Site: D = Detroit River plume, M = Maumee River plume; pred: Predator species, WA = walleye, WB = White Bass, WP = White Perch; yp: presence (1) or absence (0) of YP in predator stomachs as detected with SNP assay; YP##bands: the number of YP sized microsatellite bands detected in stomach content DNA for locus ##; YP##fish: the number of larval YP inferred from the number of microsatellite bands for microsatellite ## and the allele accumulation curve (see Supplemental Figure 1); Avefish: the average number of larval YP detected in stomach content DNA based on all 5 microsatellite loci.
Carreon-MartinezYPpredationData.csv
YP_SNP_Validation_Non-target_Ct_values
Data generated during qPCR validation of Yellow Perch SNP assay. Column headings: DNA concentration (ng/uL): final concentration of DNA in ng/uL added to validation assays; WA Ct: Cycle number at which Walleye DNA reached the amplification threshold when amplified with the Yellow Perch specific SNP assay; WB Ct: Cycle number at which White Bass DNA reached the amplification threshold when amplified with the Yellow Perch specific SNP assay; WP Ct: Cycle number at which White Perch DNA reached the amplification threshold when amplified with the Yellow Perch specific SNP assay; mean Ct: Average of all non-target predator Ct values when amplified with the Yellow Perch specific SNP assay; SD Ct: Standard Deviation of all non-target predator Ct values when amplified with the Yellow Perch specific SNP assay; SE Ct: Standard Error of all non-target predator Ct values when amplified with the Yellow Perch specific SNP assay
BasinwidePredationEstimates
Description of calculations of basin wide Yellow Perch predation mortality estimates.